Manufactured wood stairs in commercial.

[ctcray]

I have a 4' wide staircase to a basement in a building to be built with hollowcore planks for first floor. Original plan called for precast stairs, but owner now wants to build in wood. Local stair manufacturer says they have a commercial grade stair, but doesn't provide certification or calcs to back it up. From my internet searches, seems to be a common situation. The max span in my case is about 9' horizontal.

Anyone ever seen calcs for a straight, pre-built wood staircase? for 100psf? I don't want to reinvent the wheel if i don't have to.

 

[scottiesei]

Check to ensure that wood stairs meet the building type and requirement. Sometimes they need to be non-combustible. You should be able to do the calcs in a few minutes though, just get the material specs and details from the provider.

 

[SlideRuleEra]

Perhaps the Stairway Manufacturer's Association has some useful information. Here is a link

http://www.stairways.org/codes_standards.htm

http://www.SlideRuleEra.net

 

[Bagman2524]

IBC and NFPA-101 require stairs to be non-combustable. Residential (one & two family dwelling) stairs can be wood.

 

[twinnell]

Bagman,

Are you sure? We have designed 3 and 4 story timber framed condos. IBC didn't require non-combustible stairs.

 

[scottiesei]

I always thought that the stair material had to jail with the building type. I.E: if the building type was combustible and egress was designed that way, the stairs could be as well. We need an architect....(did I just say that out loud?)

 

[ctcray]

At this point, the architect is signing off on the change to wood. I know with steel, the design is often spec'd to the manufacturer/detailer. In this case (pre-built wood stairs), one manufacturer says they don't do that.

The architect doesn't want me to whip out my calc pad and design and detail new stairs, just to spec a wood staircase. I was investigating the likelyhood of actually getting a staircase that can be provided as spec'd, like steel.

Looks like that's not likely. Thanks.

 

[Bagman2524]

I stand corrected. IBC-2006 section 1009.5 all stairways shall be built of materials consistent with the type of building construction. Building Types I & II are non-combustable. Types III & IV are a mixture of combustable and non-combustable and Type V can be all combustable.